Field of the Invention
The present invention is related to plethysmographic devices. More specifically, the present invention relates to a method for determining a premature atrial contraction event using a mobile plethysmographic device.
Description of the Related Art
There is no easy method to determine if someone is suffering from a peripheral artery disease.
Peripheral artery disease is often associated with high blood pressure, diabetes, heart disease, stroke, sedentary lifestyle and aging—cholesterol and fat plaque blocks circulation to vital arteries, often in the legs and feet. Diagnosis for Peripheral Artery Disease (“PAD”) is typically done by comparing results from two blood pressure cuffs. To help determine how well a patient's blood is flowing, experienced clinicians use the ankle-brachial index, a painless, inexpensive exam, to compare blood pressure in a patient's feet to the blood pressure in his arms. Particularly lower-leg pain, is misdiagnosed and primary care doctors make referrals to orthopedic surgeons, nerve specialists and podiatrists.
Arrhythmias are caused by problems with the heart's electrical system. An arrhythmia is a heartbeat that's too fast, too slow or irregular (uneven). The electrical signals may fire too fast (tachycardia) or too slowly (bradycardia), or in an uneven (irregular) way. When you have an arrhythmia, your heart may seem to skip beats or flutter. Fibrillation is an abnormal firing of signals within an area of the heart causing a disorganized beat. Abnormal electrical signals can originate in different areas of the heart (such as the atria or ventricles) causing arrhythmias.
Tachycardia is a heart rate that exceeds the normal range. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia. Tachycardia can be caused by various factors that often are benign. However, tachycardia can be dangerous, depending on the speed and type of rhythm.
Bradycardia is the resting heart rate of under 60 beats per minute (“BPM”), although it is seldom symptomatic until the rate drops below 50 BPM. It sometimes results in fatigue, weakness, dizziness, and at very low rates fainting. A waking heart rate below 40 BPM is considered absolute bradycardia.
Sinus arrhythmia involves cyclic changes in the heart rate during breathing. It is very common in children and often found in young adults. Patients with sinus arrhythmia do not experience any cardiovascular symptoms. The sinus node rate can change with inspiration/expiration, especially in younger people. The heart rate speeds up with inspiration (since it inhibits your vagal nerve) and decreases with expiration (stimulates your vagal nerve). Sick sinus syndrome (SSS) occurs when over time the sinus node scars and becomes replaced with fibrous tissues. SSS contains a spectrum of arrhythmias including severe sinus bradycardia, tachycardic-bradycardic syndrome (tachy-brady syndrome), or sinus exit block/sinus pauses. Also known as “tachy-brady syndrome,” sick sinus syndrome is a common condition that affects the elderly, accounting for the majority of patients undergoing pacemaker implantation in the U.S.
Premature Atrial Contractions (PACs) are amongst the most common forms of arrhythmias. It is due to the premature discharge of an electrical impulse in the atrium, causing a premature contraction. A PAC is premature, because it occurs earlier than the next regular beat should have occurred.
Premature ventricular contractions (PVCs) are premature heartbeats originating from the ventricles of the heart. Premature ventricular contractions are premature because they occur before the regular heartbeat.
In atrial fibrillation, the normal regular electrical impulses generated by the sinoatrial node in the right atrium of the heart are overwhelmed by disorganized electrical impulses usually originating in the roots of the pulmonary veins. This leads to irregular conduction of ventricular impulses that generate the heartbeat. AF may occur in episodes lasting from minutes to days (paroxysmal AF) or may be permanent in nature. Many medical conditions increase the risk of AF, in particular mitral stenosis (narrowing of the mitral valve of the heart).
There is presently no simple, consistent and reliable way to diagnose and quantify PAD and its progression in patients at any stage. This is particularly true for primary care physicians who are the first providers to typically diagnose PAD. Early detection can support early preventative measures to mitigate development of the disease with attendant damage to the patient and cost. Currently, use of ultrasound to determine if there is a blockage of an artery or use of a blood pressure monitor on the leg and one on the arm simultaneously to try to ascertain a restricted blood flow are the most common means of diagnosing PAD. Doctors essentially rely on their experience and analysis.
The prior art requires ECG devices attached to a patient in order to determine if a PAC event is occurring. Due to all of this effort required to determine if a PAC event using the ECG device, most patients fail to get diagnosed. Thus, there is a need for a mobile plethysmographic device that can be worn for an extended period and provide PAC information to a user.